Kerala not susceptible to quakes, says seismologist

Kottayam: Seismologist Kusala Rajendran of Indian Institute of Science, Bangalore, says that Kerala is not susceptible to big earthquakes. She was reacting to 3.2 on the Richter scale earthquake recorded at Peechi on September 28.

“I do not think that earthquake is a serious concern in Kerala as long as the minimum quality and engineering designs are followed. Also avoid constructions in landfills without proper precautions like the piling,” the professor of the Centre for Earth Sciences, IISC, told DC.

“In my view, Kerala’s problems have more to do with landslides, water engineering, landscape management and floodplain management. While no one has died of an earthquake in the historical and recent times in Kerala look at the number of deaths in landslides and rain-related disasters.”

She said that the history of occurrence of small or low-moderate earthquakes in some parts of Kerala is not new. Wadakkanchery region has experienced such low-level seismic activity in the past, and she said, that was the reason for selecting Peechi for setting up the earthquake observatory.

“Palai and Nedumk-andam regions have also experienced slightly stro-nger tremors in the past. If you look at the mechanism of earthquakes in the stable continental regions around the world, what happens in Kerala is  nothing unusual, it is just the result of reactivation of pre-existing weak zones (fault zones that are not much older in geological sense, say compared to Himalaya for example),” she said. “Because they are older (geologically) and have undergone several cycles of deformation throughout its long tectonic history (100s of millions of years) these structures are broken down in scale, and they exist in the shallow part of the earth’s crust (within 10-15 km).

“When these structures are disturbed due to normal tectonic reasons or other factors like an excessive flow of water to these weak zones they can trigger small tremors, which are shallow, and thus felt and sometimes also heard as the energy is released at shallow depths."

Prof. Rajendran maintained that the state has sufficient earthquake monitoring mechanism.

“There are two good stations in Kerala and many in dam sites, which should be enough to monitor the seismicity,” she said.